1. Field of the Invention
The invention relates to a dust measurement system and device for measuring dust from granular matter. It relates particularly, to a closed system and device to accurately test and quantify the amount of dust in granular fertilizer at the point of storage and use in the field.
2. Description of Related Art
Methods of measuring the amount of dust in granular fertilizers in laboratories are known in the art. However, the ability to accurately test and quantify the amount of dust in granular fertilizer to evaluate dust control measures in the field is lacking in the fertilizer industry.
Related art for specifically removing dust from granular fertilizer samples includes Reference Manual IFDC-R-1 (International Fertilizer Development Center) entitled "TVA Procedures For Determining Physical Properties Of Fertilizer" describing a Tennessee Valley Authority (TVA) method for laboratory measurement of dust. The apparatus described therein attempts to remove the dust by agitating the fertilizer as it is passed through a series of grates with air blowing in the opposite direction in what may be called a distillation tower. The dust is blown out to the environment and the sample is weighed before and after testing to quantify the amount of dust.
However, the prior art device is used in a lab, generally remote from the worksite, such that a time lag of several days can occur between sample gathering and testing and evaluating the need for further dust control measures. In addition, sample gathering in the field for analysis is, by itself, time intensive, and proper containers are needed to maintain the integrity of the sample during shipping to the lab. Proper transportation to the analysis site has to be arranged including ensuring compliance with transportation and environmental related regulatory requirements. Proper sample labeling and storage arrangements are required. If samples are destroyed or misplaced, replacement samples are not readily available. In addition, if field personnel can confirm that proper dust control measures have been applied to the granular matter, then inspections and testing requirements of regulatory agencies such as the Environmental Protection Agency (EPA) and a state Department of Environmental Protection (DEP) can be waived during loading and unloading operations at shipping ports, transfer stations or production sites.
A problem associated with the TVA method mentioned above, other than the aforementioned time lag problems, is that the sample must be weighed both before and after the testing procedure. With the TVA method, granules of product may be lost during the testing procedure as a result of the open top, thus skewing the analysis to indicate higher dust readings. Losing some granules will result in a calculated higher dust content than actually exist which can result in unnecessary additional dust control agents being applied.
It is thus apparent that a need exists for a system and device which is self-contained, that is, a closed system as opposed to the open system of the device in the TVA Manual, which is easy to operate by personnel with no prior skills and minimal training needed to use the system and device, yet provides reliable dust content data for on-site assessment of dust control measures so that operators can in turn assess the effectiveness of dust control measures taken in the field.
The present invention was not obvious to those skilled in the art because on-site lab analysis is rarely done or considered in the fertilizer industry; there may be logistical problems in assembling and installing lab equipment as a permanent part of the actual production process; and prior art testing methods are sensitive to external forces such as wind or high dust in ambient air, thus impairing the effectiveness of normal testing techniques. For example, measurements taken using the TVA recommended device with its open top would be affected by surrounding winds in a high dust environment. In addition, EPA and DEP regulatory requirements have been somewhat vague regarding on-site testing requirements, thereby providing no impetus to conduct such on-site tests. Further, operators in the past have generally been more interested in qualitative information, that is, what the dust is made of, instead of quantitative information, that is, how much dust is in the fertilizer. The present invention provides a closed system which is not affected by external forces and provides valuable quantitative data from which effective dust control measures in the field can be considered.